<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        ul {
            /* 开启父容器ul的弹性盒子布局 */
            display: flex;

            justify-content: space-between;

            border: 2px solid orange;
        }

        
        li {
            list-style: none;
            width: 100px;
            height: 50px;
            border: 1px solid darkblue;
            background-color: lightblue;
        }
        
        li:nth-child(2),
        li:nth-child(3) {
            flex-grow: 1;
            background-color: pink;
        }
        
        li:nth-child(3) {
            flex-grow: 2;
        }
    </style>
</head>
<body>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
       
    </ul>
   
</body>
</html>